The Critical Problems of Christian Physicalism: Why Substance Dualism Remains Essential for Understanding Christ’s Incarnation

Introduction: The Battle for the Soul

For nearly two thousand years, Christians have believed that human beings consist of both a physical body and an immaterial soul. This view, known as substance dualism, has been the overwhelming consensus of Christian teaching throughout history. Today, however, this traditional understanding faces a significant challenge from a view called physicalism, which claims that humans are nothing more than physical bodies.

The stakes of this debate could not be higher. As J. Gresham Machen, the great Presbyterian scholar, once observed: “I think we ought to hold not only that man has a soul, but that it is important that he should know that he has a soul” (Chapter 3, “Substance Dualism and the Diachronic/Synchronic Unity of Consciousness”). This statement captures something essential about Christian faith – our understanding of human nature directly affects our understanding of salvation, eternal life, and most importantly, how God became human in Jesus Christ.

This report will demonstrate that physicalism, despite its growing popularity among some Christian academics, creates insurmountable problems for core Christian doctrines. Most critically, physicalism undermines our ability to understand how the eternal Son of God could truly become human while remaining divine. The traditional view of substance dualism, far from being an outdated relic of Greek philosophy, provides the necessary framework for maintaining orthodox Christian belief.

Part I: Understanding the Two Views

What is Physicalism?

Physicalism is the view that human beings are entirely physical entities. According to this position, there is no immaterial soul or spirit separate from the body. As R.T. Mullins explains in Chapter 8 of “Christian Physicalism?”: “Physicalism is the view that a human person is identical to, or consists only of, a physical substance. Physicalists are divided over which physical substance a human person is in fact identical to, but the two most common claims are that a human person is either identical to a human brain, or identical to a human body.”

Christian physicalists try to maintain their faith while accepting this materialist view of human nature. They argue that the Bible’s language about souls and spirits should be understood metaphorically rather than literally. They claim that advances in neuroscience have shown that all mental activities can be explained by brain processes, making the idea of an immaterial soul unnecessary.

What is Substance Dualism?

Substance dualism holds that human beings consist of two distinct substances: a material body and an immaterial soul. The soul is not merely a function or emergent property of the body, but a genuine substance in its own right. As explained in the book, “A person is a soul that has the capacity to think and perform free actions. A person is a center of consciousness that can exemplify a variety of mental properties like thought, emotion, self-reflection, self-awareness, etc.” (Chapter 8).

This view has deep biblical roots. Throughout Scripture, we find consistent teaching that humans can exist apart from their physical bodies. Jesus himself sided with the Pharisees against the Sadducees on the question of the soul’s survival after death, as we see in Matthew 22:23-33. Paul speaks of being “absent from the body but present with the Lord” (2 Corinthians 5:8), clearly indicating that personal existence continues between death and resurrection.

It’s crucial to understand that substance dualism doesn’t mean that the body is unimportant or evil. Christian dualism has always taught that humans are meant to be unified beings of body and soul. The body is good, created by God, and will be resurrected. But the soul can temporarily exist without the body, which is what happens in the intermediate state between death and resurrection.

Part II: The Common Sense of Dualism

Before examining the theological problems with physicalism, it’s worth noting that dualism aligns with universal human intuitions and experiences. As J.P. Moreland points out in Chapter 3, this common-sense view is acknowledged even by physicalist philosophers:

“Property and substance dualism are the common-sense views held by the overwhelming number of humankind now and throughout history. As Charles Taliaferro points out, this is widely acknowledged by physicalists, including Michael Levin, Daniel Dennett, David Lewis, Thomas Nagel, J. J. C. Smart, Richard Rorty, Donald Davidson, and Colin McGinn.”

This universal human intuition shouldn’t be dismissed lightly. Jaegwon Kim, a prominent philosopher, admits: “We commonly think that we, as persons, have a mental and bodily dimension… Something like this dualism of personhood, I believe, is common lore shared across most cultures and religious traditions.”

Children Are Natural Dualists

Remarkably, scientific research has shown that children naturally think in dualistic terms without being taught to do so. Henry Wellman’s research in developmental psychology demonstrates that “young children are dualists: knowledgeable of mental states and entities as ontologically different from physical objects and real [non-imaginary] events.”

This natural dualism of children suggests that the distinction between body and soul is not merely a cultural artifact or philosophical invention, but something deeply rooted in human nature itself. We don’t have to teach children to be dualists – they naturally understand themselves as having both physical and mental/spiritual dimensions.

Part III: The Irrelevance of Neuroscience for Disproving the Soul

One of the main arguments physicalists use against dualism is that modern neuroscience has somehow disproven the existence of the soul. They point to brain scans showing neural activity corresponding to thoughts and emotions, claiming this proves that the mind is nothing more than the brain. However, this argument commits a fundamental logical error.

As the book explains, finding correlations between brain states and mental states doesn’t prove that mental states are nothing but brain states. Consider an analogy: When you watch television, there is a perfect correlation between the signal received by your TV and the picture on the screen. But this doesn’t mean the TV program originates in your television set. Similarly, the brain could be receiving and processing signals from an immaterial soul.

Furthermore, neuroscience actually reveals phenomena that are difficult to explain on physicalist grounds. The unity of consciousness – our experience of being a single, unified self despite having billions of neurons firing independently – remains a mystery for physicalism. How do separate physical processes in different parts of the brain combine to create one unified experience of being “me”? Dualism provides a straightforward answer: the soul is the unifying principle that integrates these diverse brain processes into a single consciousness.

Part IV: The Problem of Personal Identity Over Time

One of the most serious philosophical problems facing physicalism concerns personal identity – what makes you the same person throughout your life. This problem has profound implications for Christian theology, particularly regarding resurrection and eternal life.

The Physical Body Constantly Changes

Science tells us that the atoms and molecules in our bodies are constantly being replaced. Most of the cells in your body are replaced every seven to ten years. The physical matter that constitutes your body today is almost entirely different from what constituted it a decade ago. If you are nothing but your physical body, then in what sense are you the same person you were ten years ago?

Physicalists struggle to answer this question coherently. They might appeal to continuity of bodily processes or psychological continuity, but these answers face serious problems. Bodily processes can be interrupted (as in cardiac arrest) without destroying personal identity. Psychological continuity can be disrupted by amnesia or unconsciousness, yet we don’t cease to exist when we sleep or forget things.

The Soul as the Basis of Identity

Substance dualism provides a clear answer to the problem of personal identity: you remain the same person throughout life because you have the same soul. The soul is the enduring, unchanging core of your identity that persists through all physical and psychological changes. As the book notes: “For dualism, the soul is the locus of self-identity. It endures continuously as the self-same substantial or subsistent entity throughout life, during the intermediate state, and after the resurrection of the body.”

This understanding of personal identity is crucial for Christian faith. When God promises eternal life, He promises that you – not someone similar to you – will live forever. When Christ promises that believers will be with Him in paradise, He means that the very same persons who trusted Him on earth will enjoy fellowship with Him in heaven. Without the soul as the basis of identity, these promises become meaningless.

Part V: The Unity of Consciousness Problem

Another major challenge for physicalism concerns what philosophers call the “unity of consciousness.” At any given moment, you have multiple experiences – you might see colors, hear sounds, feel textures, and have thoughts all simultaneously. Yet you experience these as unified in a single consciousness. You don’t experience five separate streams of consciousness; you experience one consciousness with multiple contents.

If physicalism is true, and you are nothing but a collection of physical particles and processes, why do you have unified conscious experience? The brain consists of billions of neurons, each doing its own thing. Different parts of the brain process different types of information – visual processing in one area, auditory in another, memory in yet another. But somehow all this diverse neural activity results in a single, unified experience of being you.

Physicalism has no good explanation for this unity. It’s what philosopher David Chalmers calls the “binding problem” – how do separate physical processes bind together to create unified consciousness? Some physicalists appeal to neural synchronization or information integration, but these are descriptions of the problem, not solutions. Why should synchronized neural firing create unified experience rather than just synchronized separate experiences?

Dualism, by contrast, has a natural explanation: the soul is the unifying principle. All the diverse brain processes are experienced by one soul, which naturally explains why consciousness is unified. The soul is the single subject that has all these experiences, binding them together into one consciousness.

Part VI: The Incarnation Problem – The Heart of the Matter

We now come to the most serious theological problem with physicalism: it makes the incarnation of Christ either impossible or heretical. This is not a minor doctrinal dispute but strikes at the very heart of Christian faith. As R.T. Mullins demonstrates in Chapter 8 of “Christian Physicalism?”, physicalism cannot adequately account for how God became human in Jesus Christ without falling into ancient heresies that the church has condemned.

Understanding the Incarnation

The doctrine of the incarnation teaches that the eternal Son of God, the second person of the Trinity, became human while remaining fully divine. Jesus Christ is one person with two natures – fully God and fully human. This doctrine was carefully formulated at the Council of Chalcedon in 451 AD and refined at subsequent councils.

The Chalcedonian definition states that Christ is “truly God and truly man, consisting also of a reasonable soul and body; of one substance with the Father as regards his Godhead, and at the same time of one substance with us as regards his manhood.” Notice that the definition explicitly mentions that Christ has a human soul – not just a human body.

The Physicalist Dilemma

If physicalism is true and humans are nothing but physical bodies, then for the Son of God to become human, He would have to become a physical body. As Mullins explains: “On a physicalist Christology, the Son does not assume a human soul. Instead, the Son becomes identical to a human body.”

This creates an immediate problem. The Son of God is eternal, immaterial, and divine. How can an immaterial divine person become identical to a material body? It seems logically impossible, like asking a number to become a color. Brian Leftow and Robin Le Poidevin, philosophers who have examined this issue, conclude that “such a thing is impossible because the Son—an immaterial thing—cannot become wholly material.”

Part VII: The Two Sons Worry – A Fatal Flaw in Physicalist Christology

Even if we set aside the logical problem of an immaterial person becoming a material body, physicalism faces another devastating christological problem that R.T. Mullins calls “the Two Sons Worry.” This problem shows that physicalism inadvertently commits the ancient heresy of Nestorianism.

What is Nestorianism?

Nestorianism, condemned at the Council of Ephesus in 431 AD, is the heresy that says there are two persons in Christ – a divine person (the Son of God) and a human person (Jesus of Nazareth). Orthodox Christianity insists that Christ is one person, not two. There is only one “who” in Jesus Christ, even though He has two natures (divine and human).

The early church developed a crucial distinction to avoid this heresy: the anhypostasia/enhypostasia principle. This principle, affirmed at the Fifth Ecumenical Council (Constantinople II, 553 AD), states that Christ’s human nature would not and could not exist as a person apart from being assumed by the divine Son. In other words, there never was and never could be a human person “Jesus” separate from the divine Son.

How Physicalism Falls into Nestorianism

Here’s where physicalism runs into trouble. According to physicalism, a complete human person is simply a living human body. If the Son assumes a human body (as physicalists claim happens in the incarnation), then He assumes something that would be a complete human person on its own.

As Mullins explains: “On physicalism, a human person is identical to a human body. A complete human person is a living human body. On the physicalist incarnation endorsed by Merricks, God the Son becomes completely identical to a human body. It seems like it is metaphysically possible for the Son’s body to exist without the incarnation. If this body were to exist without the incarnation, it would be a complete human person.”

This violates the anhypostasia/enhypostasia principle. The human body of Jesus would be a complete person even without the Son, which means there are effectively two persons – the divine Son and the human body-person. That’s Nestorianism.

The Physicalist Response Fails

A physicalist might respond that the particular body of Jesus only came into existence through the virgin birth, which was a miracle performed for the purpose of the incarnation. Therefore, they might argue, this body would never have existed without the incarnation.

But this response doesn’t work. As Mullins points out: “It is metaphysically possible for the Holy Spirit to perform the miracle of a virgin birth without an incarnation. If this is a metaphysical possibility, then it is possible that the particular body of Jesus could come into existence without being incarnated by the Son.”

The problem is that physicalism makes the human nature of Christ too independent. On physicalism, the human body is already a complete person. Adding the divine Son to it would create two persons, not one. This is precisely what the church condemned as heresy.

Part VIII: How Dualism Avoids These Problems

Substance dualism, by contrast, provides a coherent framework for understanding the incarnation without falling into heresy. Let’s see how the traditional dualist understanding navigates these christological challenges.

The Three-Part Christology

Traditional Christian theology has understood Christ as consisting of three “parts” (using this term loosely): the divine Son, a human soul, and a human body. The divine Son assumes or takes to Himself a complete human nature consisting of a rational soul and a physical body. This is why the Chalcedonian definition specifically mentions that Christ has a “reasonable soul and body.”

This three-part Christology allows Christ to be fully human (having everything essential to human nature – body and soul) while remaining fully divine (the divine Son never ceases to be God). The divine person of the Son is the one “who” that unites both natures.

Addressing the Two Sons Worry

Some physicalists have argued that dualism also faces the Two Sons problem. After all, if Christ has a human soul with its own will (as orthodox theology teaches), doesn’t that create two persons – the divine Son and the human soul?

Andrew Loke has developed a sophisticated response to this challenge called the Divine Preconscious Model (DPM). On this model, the Son’s divine mind divides at the incarnation to include both a divine preconscious and a human preconscious. The human preconscious cannot exist separately from the Son – it is a mode or aspect of the Son’s own consciousness, not a separate person.

As Loke explains, this model “can easily account for the anhypostasia/enhypostasia constraint. The human nature of Christ simply would not count as a full human person apart from the incarnation. The Son only divides His mind into a divine and human preconscious at the incarnation for the purposes of becoming human. This human preconscious of the Son cannot possibly exist separated from the Son.”

Part IX: Biblical Evidence for Dualism

Having examined the philosophical and theological problems with physicalism, we must now turn to Scripture itself. What does the Bible teach about human nature? The evidence overwhelmingly supports substance dualism.

The Intermediate State

One of the clearest biblical teachings supporting dualism is the intermediate state – the condition of believers between death and resurrection. Scripture consistently teaches that believers continue to exist consciously with Christ even while their bodies lie in the grave.

Paul expresses this clearly in Philippians 1:23-24: “I am torn between the two: I desire to depart and be with Christ, which is better by far; but it is more necessary for you that I remain in the body.” Paul contrasts being “in the body” with departing to be “with Christ.” If humans are nothing but bodies, this statement makes no sense.

Similarly, in 2 Corinthians 5:8, Paul says, “We are confident, I say, and would prefer to be away from the body and at home with the Lord.” Again, Paul envisions existence apart from the body, which is impossible if physicalism is true.

Jesus himself taught the reality of conscious existence after death. To the thief on the cross, He promised, “Today you will be with me in paradise” (Luke 23:43). Since their bodies would be dead and buried that day, Jesus must be referring to their souls being together in paradise.

The Rich Man and Lazarus

In Luke 16:19-31, Jesus tells the story of the rich man and Lazarus. After death, both men are conscious and able to communicate – Lazarus in “Abraham’s bosom” (paradise) and the rich man in torment. Their bodies are in the grave, yet they exist as conscious persons. While some argue this is merely a parable, Jesus presents it as describing real conditions in the afterlife.

The Souls Under the Altar

In Revelation 6:9-11, John sees “under the altar the souls of those who had been slain because of the word of God and the testimony they had maintained.” These souls cry out to God and are given white robes to wear. They are conscious, can speak, and can wear robes – all while their bodies remain dead on earth. This is a clear depiction of souls existing apart from bodies.

Moses and Elijah at the Transfiguration

At the transfiguration (Matthew 17:1-8), Moses and Elijah appear and talk with Jesus. Moses had been dead for over a thousand years, his body buried in an unknown location. Yet he appears as a recognizable person, conscious and able to converse. This demonstrates the soul’s survival after bodily death.

Part X: Biblical Verses Supporting Substance Dualism

The following table presents key biblical passages that support the doctrine of substance dualism – the view that humans possess both a material body and an immaterial soul/spirit that can exist separately:

Scripture Reference	Text	Dualistic Implication
Genesis 2:7	“Then the LORD God formed a man from the dust of the ground and breathed into his nostrils the breath of life, and the man became a living being.”	Describes humans as a combination of physical body (dust) and divine breath/spirit
Ecclesiastes 12:7	“The dust returns to the ground it came from, and the spirit returns to God who gave it.”	Clear separation of body and spirit at death
Matthew 10:28	“Do not be afraid of those who kill the body but cannot kill the soul. Rather, be afraid of the One who can destroy both soul and body in hell.”	Jesus explicitly distinguishes between body and soul; soul survives bodily death
Luke 23:43	“Jesus answered him, ‘Truly I tell you, today you will be with me in paradise.'”	Conscious existence in paradise immediately after bodily death
Luke 23:46	“Jesus called out with a loud voice, ‘Father, into your hands I commit my spirit.’ When he had said this, he breathed his last.”	Jesus commits His spirit to the Father as His body dies
Acts 7:59	“While they were stoning him, Stephen prayed, ‘Lord Jesus, receive my spirit.'”	Stephen’s spirit goes to Jesus while his body is killed
2 Corinthians 5:1-8	“We know that if the earthly tent we live in is destroyed, we have a building from God… We are confident, I say, and would prefer to be away from the body and at home with the Lord.”	Paul describes being “away from the body” yet “at home with the Lord”
2 Corinthians 12:2-3	“I know a man in Christ who fourteen years ago was caught up to the third heaven. Whether it was in the body or out of the body I do not know—God knows.”	Paul acknowledges the possibility of experiences outside the body
Philippians 1:21-24	“For to me, to live is Christ and to die is gain… I desire to depart and be with Christ, which is better by far; but it is more necessary for you that I remain in the body.”	Paul contrasts remaining “in the body” with departing to be with Christ
1 Thessalonians 5:23	“May your whole spirit, soul and body be kept blameless at the coming of our Lord Jesus Christ.”	Distinguishes between spirit, soul, and body as aspects of human nature
Hebrews 4:12	“For the word of God is alive and active… it penetrates even to dividing soul and spirit, joints and marrow.”	Distinguishes between soul/spirit and physical body (joints/marrow)
Hebrews 12:23	“You have come… to the spirits of the righteous made perfect.”	Spirits of deceased believers exist in heaven
James 2:26	“As the body without the spirit is dead, so faith without deeds is dead.”	Body and spirit are distinct; body dies when spirit departs
1 Peter 3:18-19	“He was put to death in the body but made alive in the Spirit. After being made alive, he went and made proclamation to the imprisoned spirits.”	Distinguishes between bodily death and spiritual activity
Revelation 6:9-11	“I saw under the altar the souls of those who had been slain because of the word of God… They called out in a loud voice… Then each of them was given a white robe.”	Souls of martyrs conscious and active in heaven before resurrection
Revelation 20:4	“I saw the souls of those who had been beheaded because of their testimony about Jesus… They came to life and reigned with Christ a thousand years.”	Souls exist before being reunited with resurrected bodies

Part XI: The Problem of the Resurrection for Physicalism

The doctrine of bodily resurrection poses additional serious challenges for physicalism. If humans are nothing but physical bodies, what happens at the resurrection? This question reveals deep problems with physicalist eschatology (the study of last things).

The Continuity Problem

According to physicalism, when you die, you cease to exist entirely. There is no soul that survives death. At the resurrection, God would have to recreate you from scratch. But this raises a crucial question: Would the resurrected person really be you, or just a copy of you?

Think about it this way: If God created an exact duplicate of you right now, complete with all your memories and personality, would that duplicate be you? Most people would say no – it would be a copy, a different person who happens to be exactly like you. But if physicalism is true, that’s essentially what the resurrection would be – God creating a copy of you after you’ve ceased to exist.

As John Cooper explains in his critique of physicalist resurrection: “For dualism, the soul is the locus of self-identity. It endures continuously as the self-same substantial or subsistent entity throughout life, during the intermediate state, and after the resurrection of the body. It remains numerically identical even if one’s personality or body changes radically.”

Without the soul to maintain personal identity through death, physicalism cannot guarantee that the resurrected person is really you rather than a replica. This undermines the biblical promise of personal resurrection and eternal life.

The Gap Problem

Physicalism creates a temporal gap in personal existence. If you cease to exist at death and are recreated at the resurrection, there’s a period of time when you simply don’t exist. This contradicts numerous biblical passages that describe conscious existence between death and resurrection.

Consider Jesus’s promise to the thief on the cross: “Today you will be with me in paradise.” If physicalism is true, this promise is false. The thief couldn’t be with Jesus in paradise that day because he would have ceased to exist when he died. At best, a copy of him could be with Jesus after the resurrection.

Part XII: Why Some Christians Embrace Physicalism Despite These Problems

Given all these serious problems with physicalism, why would any Christian adopt this view? Understanding their motivations helps us address their concerns while showing why abandoning dualism is unnecessary and harmful.

The Influence of Scientific Materialism

Many Christian physicalists have been influenced by the prevailing materialism in academic circles. They feel pressure to conform to what they perceive as the “scientific” view of human nature. As the book notes: “So far as I can tell, the main reason for the change of viewpoint is the idea that it is somehow required by advances in neuroscience.”

However, as we’ve seen, neuroscience doesn’t actually disprove the soul. The correlation between brain states and mental states is perfectly compatible with dualism. The pressure to adopt physicalism comes not from science itself but from the philosophical materialism that many scientists assume.

Misunderstanding Historical Theology

Some Christian physicalists claim that dualism is a Greek philosophical import foreign to biblical thought. They argue that Hebrew thought was “holistic” and didn’t distinguish between body and soul. This claim, however, doesn’t stand up to scrutiny.

While it’s true that Hebrew thought emphasized the unity of the human person, this doesn’t mean the Hebrews denied the distinction between body and soul. The Old Testament frequently refers to the soul (nephesh) and spirit (ruach) as distinct from the body. The idea that biblical writers were monists is a modern scholarly construct, not something derived from careful exegesis of the texts themselves.

The Desire to Avoid “Gnostic” Dualism

Many physicalists worry that dualism leads to a devaluation of the body and physical world, similar to ancient Gnosticism. Gnostics taught that matter was evil and only spirit was good, leading to either extreme asceticism or libertinism.

But Christian dualism is nothing like Gnosticism. Christian dualists affirm that:

• The body is good, created by God (Genesis 1:31)
• The body is the temple of the Holy Spirit (1 Corinthians 6:19)
• The body will be resurrected and glorified (1 Corinthians 15)
• What we do in the body matters for eternity (2 Corinthians 5:10)

Christian dualism teaches that humans are meant to be embodied souls. The separation of soul and body at death is unnatural and temporary, to be remedied at the resurrection. This is completely different from Gnostic hatred of the body.

Part XIII: The Pastoral Implications

The debate between physicalism and dualism isn’t merely academic – it has profound implications for Christian life and ministry. How we understand human nature affects how we approach death, comfort the grieving, understand salvation, and live the Christian life.

Comfort in the Face of Death

For two thousand years, Christians have comforted grieving believers with the assurance that their loved ones are “with the Lord.” This comfort is based on the conviction that while the body lies in the grave, the soul is in conscious fellowship with Christ in heaven.

Physicalism destroys this comfort. If physicalism is true, deceased believers aren’t with the Lord – they don’t exist at all. They’ve been annihilated, waiting to be recreated (or have copies of themselves created) at the resurrection. As Cooper points out: “One must have sufficient reason for denying or completely revising what the historic Christian church has affirmed as the teaching of Scripture and proclaimed to comfort millions of people who have mourned at gravesides.”

The Nature of Death

Scripture presents death as an enemy, but not the ultimate enemy. For believers, death is transformed from a curse into a doorway. Paul can even say, “to die is gain” (Philippians 1:21) because death means being “with Christ, which is better by far” (Philippians 1:23).

But if physicalism is true, death isn’t gain – it’s total loss. It’s the complete cessation of existence. How can Paul say it’s “better by far” to cease existing? The physicalist must either deny Paul’s meaning or claim he was mistaken about what death entails.

Understanding Spiritual Life

The Bible frequently speaks of spiritual realities that are difficult to understand on physicalist terms. We’re told to “set your minds on things above” (Colossians 3:2), to “walk by the Spirit” (Galatians 5:16), and that “our struggle is not against flesh and blood, but against the rulers, against the authorities, against the powers of this dark world and against the spiritual forces of evil in the heavenly realms” (Ephesians 6:12).

If humans are purely physical beings, what does it mean to have spiritual struggles? How do we interact with spiritual realities? Physicalism tends to reduce spiritual language to metaphor, robbing it of its power and reality.

Part XIV: Addressing Common Objections to Dualism

Despite the strong case for dualism, critics raise various objections. Let’s address the most common ones:

Objection 1: “Dualism Can’t Explain Mind-Body Interaction”

Critics argue that if the soul is immaterial and the body is material, how can they interact? This is known as the interaction problem, famously raised by Princess Elisabeth against Descartes.

Response: While the exact mechanism of soul-body interaction remains mysterious, this doesn’t disprove dualism. Consider that physicalists themselves accept mysterious interactions. How does consciousness arise from purely physical processes? This is the “hard problem of consciousness” that physicalists cannot solve. Furthermore, Christians already believe in spirit-matter interaction – God, who is spirit, created and sustains the physical universe. If God can interact with matter, why couldn’t human souls?

Objection 2: “Brain Damage Affects Personality and Consciousness”

Critics point out that brain injuries can change personality, impair memory, and affect consciousness. Doesn’t this prove that the mind is just the brain?

Response: Dualists don’t deny that the brain affects mental function. The soul operates through the brain while embodied, so brain damage naturally affects how the soul can express itself. Think of a skilled pianist with damaged hands – the damage doesn’t eliminate their musical knowledge and ability, but it prevents proper expression of that ability. Similarly, brain damage doesn’t eliminate the soul but impairs its ability to function through the damaged brain.

Objection 3: “Dualism Is Scientifically Outdated”

Some claim that dualism is a pre-scientific view that modern neuroscience has disproven.

Response: As we’ve seen, neuroscience hasn’t disproven dualism. Even physicalist philosopher Nancey Murphy admits that “no amount of evidence from neuroscience can prove a physicalist view of the mental.” Science studies physical processes; it cannot prove or disprove the existence of non-physical realities. The claim that science has disproven the soul is not a scientific claim but a philosophical one – specifically, the philosophy of materialism.

Part XV: The Theological Consequences of Abandoning Dualism

When Christians abandon dualism for physicalism, the consequences ripple throughout their theology. Let’s examine how physicalism undermines various Christian doctrines:

The Image of God

Scripture teaches that humans are made in God’s image (Genesis 1:27). Traditionally, this has been understood to refer primarily to our spiritual nature – our capacity for reason, morality, relationships, and worship. God is spirit (John 4:24), so His image in us must be primarily spiritual.

If physicalism is true and humans are purely physical, in what sense do we image a spiritual God? Physicalists must either redefine the image of God in purely functional terms (what we do rather than what we are) or admit that physical beings cannot truly image a spiritual God.

The Nature of Sin

The Bible teaches that sin affects the whole person but is primarily a spiritual problem. Jesus said that evil comes from within, from the heart (Mark 7:21-23). Paul speaks of the “sinful nature” or “flesh” warring against the Spirit (Galatians 5:17).

If humans are purely physical, sin becomes merely a biological malfunction or environmental conditioning. This reduces moral responsibility and undermines the need for spiritual redemption. Why would we need spiritual rebirth if we’re not spiritual beings?

Sanctification

The process of sanctification involves the transformation of our inner being by the Holy Spirit. We’re told to “be transformed by the renewing of your mind” (Romans 12:2) and that “the Spirit himself testifies with our spirit that we are God’s children” (Romans 8:16).

How can the Holy Spirit testify with our spirit if we don’t have a spirit? How can we be spiritually transformed if we’re purely physical? Physicalism reduces sanctification to behavioral modification rather than spiritual transformation.

Prayer and Worship

Jesus taught that “true worshipers will worship the Father in spirit and truth” (John 4:23). Prayer is fundamentally spiritual communication with God. While prayer certainly involves our bodies and brains, it’s primarily a spiritual activity.

If humans are purely physical, prayer becomes problematic. How does a physical being communicate with a spiritual God? Physicalists might say God reads our brain states, but this reduces prayer to physical processes rather than spiritual communion.

Part XVI: Why the Early Church Rejected Physicalist Views

It’s important to understand that the early church faced and rejected views similar to modern physicalism. The early Christians were not naive about these issues – they carefully thought through the implications of different views of human nature.

The Sadducees

In Jesus’s time, the Sadducees denied the resurrection and the existence of spirits (Acts 23:8). They held a materialist view of human nature. Jesus explicitly opposed them, siding with the Pharisees who believed in the soul’s survival after death. In Matthew 22:23-33, Jesus refutes the Sadducees by pointing to God’s statement, “I am the God of Abraham, the God of Isaac, and the God of Jacob,” arguing that God is “not the God of the dead but of the living.”

Jesus’s argument only makes sense if Abraham, Isaac, and Jacob continue to exist after bodily death. If they ceased to exist when they died (as physicalism suggests), God would be the God of the non-existent, not the living.

Early Heresies

The early church also dealt with various heresies that involved inadequate views of human nature. Some groups taught that Christ only appeared to have a human body (Docetism), while others taught that the divine Christ temporarily inhabited a human body (forms of Adoptionism). These heresies were rejected because they failed to affirm the full humanity of Christ.

Interestingly, the church’s response consistently affirmed that full humanity requires both body and soul. The Chalcedonian definition explicitly states that Christ has a “reasonable soul and body.” The church fathers understood that reducing human nature to either pure spirit or pure matter was inadequate.

The Witness of the Church Fathers

The early church fathers unanimously affirmed the existence of the soul and its survival after death. From Clement of Rome to Irenaeus, from Justin Martyr to Augustine, the testimony is consistent: humans have souls that can exist apart from their bodies.

These were not philosophically unsophisticated thinkers who uncritically absorbed Greek philosophy. Many of them, like Tertullian, were actually suspicious of Greek philosophy. Yet they affirmed dualism because they found it clearly taught in Scripture and necessary for Christian doctrine.

Part XVII: The Modern Revival of Christian Physicalism

Despite this overwhelming historical testimony, physicalism has gained ground among some Christian academics in recent decades. Understanding this trend helps us see why it’s important to defend traditional dualism.

The Rise of “Nonreductive Physicalism”

The most popular form of Christian physicalism today is called “nonreductive physicalism.” Advocates like Nancey Murphy argue that humans are purely physical but that mental properties are not reducible to physical properties. They claim this preserves human dignity and responsibility while being compatible with modern science.

However, nonreductive physicalism faces serious philosophical problems. If mental properties are genuinely irreducible to physical properties, in what sense is the view truly physicalist? It seems to smuggle in dualism while denying the label. On the other hand, if mental properties are nothing over and above physical properties differently described, then the view collapses into reductive physicalism with all its problems.

The “Constitution View”

Some Christian physicalists like Kevin Corcoran propose a “constitution view” where humans are constituted by but not identical to their bodies. They argue this allows for the possibility of existing with different bodies in the resurrection.

But this view faces the same problems we’ve discussed. If I can be constituted by a completely different body, what makes me the same person? Without the soul as the bearer of identity, the constitution view cannot adequately account for personal identity through death and resurrection.

Emergent Dualism

William Hasker proposes “emergent dualism” where the soul emerges from the body but then becomes capable of independent existence. This is an attempt to combine insights from both physicalism and dualism.

While emergent dualism is an improvement over strict physicalism, it still faces problems. How does something immaterial emerge from purely material processes? And if the soul can exist independently once emerged, why not accept traditional dualism from the start?

Part XVIII: Practical Guidance for Christian Believers

Given the serious problems with physicalism and the strong biblical and theological case for dualism, how should Christian believers approach this issue?

Don’t Be Intimidated by Academic Pressure

Many Christians feel pressured to abandon dualism because it seems intellectually unsophisticated. But as we’ve seen, dualism has strong philosophical support and is not disproven by science. Some of the greatest minds in history have been dualists, and many leading philosophers today defend forms of dualism.

Remember that the pressure against dualism often comes not from evidence but from the materialist worldview that dominates secular academia. Christians should not abandon biblical truth to gain academic respectability.

Maintain Biblical Balance

While affirming dualism, we must maintain the biblical balance that values both body and soul. We are embodied souls, meant to be unified beings. The body is not a prison for the soul but its proper dwelling place in this life. We should care for our bodies as temples of the Holy Spirit while recognizing that we are more than our bodies.

Apply This Understanding to Daily Life

Understanding that we have souls affects how we approach many aspects of life:

• In suffering: Physical and mental suffering, while real and significant, cannot destroy our essential selves. Our souls are secure in God’s hands.
• In death: Death is not the end but a temporary separation of soul and body. Believers immediately enter Christ’s presence.
• In worship: We worship not just with our bodies but with our whole being, spirit and truth.
• In ethics: We are responsible for our actions because we are more than physical processes. We have genuine free will rooted in our spiritual nature.

Be Prepared to Give an Answer

As Christians, we should be prepared to explain and defend the biblical view of human nature. When discussing these issues:

• Start with Scripture – show the clear biblical teaching about the soul
• Address scientific objections – explain that science doesn’t disprove the soul
• Point out the problems with physicalism – especially for core Christian doctrines
• Appeal to common human intuitions – most people naturally believe they are more than their bodies
• Show the practical implications – how different views affect life and faith

Part XIX: The Incarnation as the Ultimate Test Case

We return now to the incarnation as the ultimate test case for any Christian anthropology. The doctrine of the incarnation is not peripheral to Christian faith – it stands at the very center. As the Apostle John writes, “Every spirit that acknowledges that Jesus Christ has come in the flesh is from God” (1 John 4:2).

Why the Incarnation Matters So Much

The incarnation is essential to salvation. Only someone who is fully God can provide infinite atonement for sin. Only someone who is fully human can represent humanity and die in our place. Jesus must be both fully God and fully human for salvation to be possible.

This is why the church has always been so careful about Christology. Errors about Christ’s nature undermine the gospel itself. If Jesus isn’t fully God, His death can’t save us. If He isn’t fully human, He can’t be our representative.

How Physicalism Undermines the Incarnation

As we’ve seen, physicalism creates multiple problems for understanding the incarnation:

1. The Impossibility Problem: If humans are purely physical and the Son of God is purely spiritual, the incarnation requires the impossible transformation of an immaterial being into a material one.

2. The Nestorianism Problem: If the Son assumes a human body that would be a complete person on its own (as physicalism suggests), we end up with two persons in Christ.

3. The Docetism Problem: If the Son can’t truly become physical (as seems logically necessary), then He only appears to be human, which is the heresy of Docetism.

4. The Apollinarianism Problem: Some physicalists might try to solve these problems by saying the divine Son replaces the human mind/soul. But this was condemned as heresy because it means Christ isn’t fully human.

The Success of Dualist Christology

Traditional dualist Christology avoids all these problems. The divine Son assumes a complete human nature consisting of a rational soul and body. He doesn’t become the soul (avoiding Apollinarianism) or become identical to the body (avoiding the impossibility problem). Instead, He unites human nature to Himself in a personal union.

The human soul and body of Christ have no independent personal existence apart from the Son (satisfying the anhypostasia/enhypostasia principle). Yet Christ possesses everything necessary for full humanity. This preserves both the full divinity and full humanity of Christ without contradiction or confusion.

Part XX: Responding to Physicalist Attempts to Save the Incarnation

Some Christian physicalists have attempted to develop theories of the incarnation compatible with their view of human nature. Let’s examine why these attempts fail.

Trenton Merricks’s Proposal

Philosopher Trenton Merricks, a prominent Christian physicalist, argues that the Son becomes identical to a human body at the incarnation. He claims this is no more problematic than dualism’s claim that human souls become embodied.

But there’s a crucial difference. In dualism, the soul doesn’t become a body – it becomes united to a body while remaining distinct from it. The soul and body form a union but retain their distinct natures. Merricks, however, requires the divine Son to literally become a physical body, which seems metaphysically impossible.

Furthermore, Merricks cannot escape the Two Sons Worry. If the human body of Jesus would be a complete human person on its own (as physicalism requires), then we have two persons even if the Son becomes “identical” to that body. The identity claim doesn’t solve the problem; it merely obscures it.

The “Concrete View” Alternative

Some physicalists adopt what’s called a “concrete view” of the incarnation, where the Son doesn’t change but rather assumes human nature by taking on the physical components required for humanity. On physicalism, this would mean taking on a human body.

But this view faces the same fundamental problem: on physicalism, a living human body is a person. If the Son assumes a human body that would be a person on its own, we have Nestorianism. The concrete view doesn’t solve the problem; it just describes it differently.

The “Relational” Solution

Some physicalists argue that what makes Christ’s humanity not a separate person is its unique relationship to the divine Son. The humanity exists only in relation to the Son and therefore isn’t an independent person.

But this solution is ad hoc and unconvincing. On physicalism, a living human body is a person by virtue of what it is, not by virtue of its relations. Adding a special relationship to the divine Son doesn’t change the fact that, according to physicalism, a living human body constitutes a person. We still end up with two persons.

Part XXI: The Broader Theological Vision

The debate between physicalism and dualism isn’t just about abstract philosophy or isolated doctrines. It’s about competing visions of reality, humanity, and God’s purposes for creation.

The Physicalist Vision

Physicalism presents a flattened, one-dimensional view of reality. Everything is physical, operating according to physical laws. While Christian physicalists affirm God’s existence, they see humans as purely creatures of this physical realm. Spiritual language becomes metaphorical, pointing to complex physical realities rather than genuine spiritual dimensions.

This vision struggles to make sense of the grand biblical narrative. Why would a spiritual God create purely physical beings in His image? How can physical beings have genuine communion with a spiritual God? Why does Scripture constantly speak in dualistic terms if monism is true?

The Dualist Vision

Dualism presents a richer, multi-dimensional view of reality. The universe contains both physical and spiritual realities, interacting in complex ways. Humans, as embodied souls, are citizens of both realms – genuinely physical yet genuinely spiritual.

This vision makes sense of the biblical narrative. Humans can image a spiritual God because we have spiritual souls. We can commune with God spirit to spirit. Death is not ultimate because our essential selves transcend the physical. The incarnation is possible because human nature already involves both physical and spiritual dimensions.

The Eschatological Hope

The Bible presents our ultimate hope as resurrection – not escape from the body but the redemption and glorification of the body. This hope makes most sense within a dualist framework.

In dualism, the soul maintains personal identity through death, ensuring that the very same person who died will be raised. The resurrection reunites soul and body, restoring humans to our intended wholeness but in a glorified state. We will be what we were meant to be – embodied souls in perfect communion with God and each other.

Physicalism struggles to maintain this hope coherently. Without souls to preserve identity through death, resurrection becomes recreation of copies rather than restoration of persons. The biblical promise of eternal life becomes problematic when persons cease to exist at death.

Part XXII: Practical Implications for Ministry and Discipleship

The debate over human nature has significant implications for Christian ministry and discipleship. How we understand human beings affects how we approach evangelism, pastoral care, spiritual formation, and ethics.

Evangelism and Apologetics

When sharing the gospel, we appeal to people’s spiritual awareness and need. We speak of sin as a spiritual problem requiring spiritual rebirth. We proclaim that humans are made for relationship with God and that this relationship transcends physical death.

If physicalism is true, this message must be radically reinterpreted. Sin becomes merely dysfunctional behavior, salvation becomes life improvement, and eternal life becomes eventual recreation after temporary non-existence. The gospel loses much of its power and coherence.

In apologetics, dualism provides common ground with most people’s intuitions about themselves. Even atheists typically believe they are more than their bodies. This intuitive dualism can be a starting point for conversations about spiritual reality and the existence of God.

Pastoral Care

In counseling and pastoral care, understanding humans as embodied souls provides a framework for addressing the whole person. Physical problems affect spiritual well-being, and spiritual problems manifest physically. Yet the distinction helps us recognize that not all problems are purely physical or purely spiritual.

When ministering to the dying, the conviction that the soul survives death provides genuine comfort. We can assure believers that death is not the end, that they will immediately be with Christ, and that their loved ones in Christ are not lost but gone ahead.

Physicalism undermines this pastoral comfort. What comfort is there in telling dying believers they will cease to exist, hoping God will recreate them (or copies of them) someday? How do we console the grieving if their loved ones no longer exist?

Spiritual Formation

Christian discipleship involves the transformation of the whole person, but especially the inner person. We are to be “transformed by the renewing of your mind” (Romans 12:2) and to “take captive every thought to make it obedient to Christ” (2 Corinthians 10:5).

This emphasis on inner transformation makes sense if we have souls that can be shaped by the Holy Spirit. Prayer, meditation, worship, and other spiritual disciplines work on our spiritual nature, gradually conforming us to Christ’s image.

If physicalism is true, spiritual formation reduces to behavior modification and brain training. While these have their place, they miss the deeper spiritual transformation that Scripture emphasizes.

Ethics and Moral Responsibility

Christian ethics assumes genuine moral responsibility, which requires genuine free will. We make real choices for which we are accountable to God. This responsibility makes most sense if we have souls that transcend physical determinism.

While some physicalists argue for compatibilist free will, this is a weakened notion of freedom that many find inadequate for genuine moral responsibility. If our choices are simply the result of physical processes in our brains, determined by prior physical states and the laws of nature, in what sense are we truly responsible?

Dualism provides a robust foundation for moral responsibility. The soul, as an immaterial substance, can be a genuine source of free choices not wholly determined by physical processes. This makes sense of biblical teaching about judgment, reward, and punishment.

Part XXIII: The Testimony of Christian Experience

Throughout history, Christians have reported experiences that make most sense within a dualist framework. While experience must be interpreted through Scripture, these consistent testimonies provide additional support for dualism.

Near-Death Experiences

Many Christians have reported near-death experiences where they seemed to leave their bodies and encounter spiritual realities. While the interpretation of such experiences is debated, they consistently involve a sense of existing apart from one’s body.

These experiences align with biblical accounts. Paul speaks of being “caught up to the third heaven” and being unsure whether he was “in the body or out of the body” (2 Corinthians 12:2-3). John describes being “in the Spirit” when receiving his visions (Revelation 1:10).

While physicalists attempt to explain these experiences in purely neurological terms, the experiencers themselves consistently report them as genuine out-of-body experiences. Some report observing verifiable events they couldn’t have known about through normal physical means.

Spiritual Warfare

The Bible teaches that Christians engage in spiritual warfare against spiritual forces of evil (Ephesians 6:12). Many Christians report experiences of spiritual oppression, demonic attack, and victory through spiritual means like prayer and fasting.

These experiences make sense if humans have a spiritual dimension that can interact with spiritual beings. If we are purely physical, it’s unclear how we could engage in genuinely spiritual warfare or be affected by spiritual entities.

The Witness of the Spirit

Romans 8:16 says, “The Spirit himself testifies with our spirit that we are God’s children.” Christians throughout history have testified to this inner witness of the Spirit – a deep, spiritual assurance of salvation that transcends mere intellectual belief or emotional feeling.

This spiritual witness makes sense if we have spirits that can commune with God’s Spirit. If we are purely physical, this testimony becomes difficult to understand as anything more than a brain state or psychological phenomenon.

Part XXIV: The Future of the Debate

As we look to the future, the debate between physicalism and dualism will likely continue to be significant for Christian theology and apologetics. Several factors will shape this ongoing discussion.

Advances in Neuroscience

Continued advances in neuroscience will provide more data about brain function and its relationship to consciousness and behavior. Physicalists will likely claim these advances support their view, but as we’ve seen, correlation between brain states and mental states doesn’t prove identity.

Christians should welcome genuine scientific advances while maintaining that science cannot disprove spiritual realities. We should be prepared to show how new discoveries are compatible with dualism and may even point to the inadequacy of purely physical explanations of human nature.

Philosophical Developments

The “hard problem of consciousness” continues to challenge physicalist philosophy of mind. How does subjective, first-person conscious experience arise from objective, third-person physical processes? This problem may lead more philosophers to consider dualist alternatives.

Christians should engage with these philosophical discussions, showing how dualism provides resources for addressing problems that physicalism cannot solve. We should also continue developing sophisticated defenses of dualism that engage with contemporary philosophical concerns.

Theological Reflection

As the implications of physicalism for Christian doctrine become clearer, more theologians may recognize its inadequacy. The incarnation problem we’ve explored in detail is just one of many theological difficulties physicalism creates.

Churches and seminaries need to teach clear thinking about human nature and its theological implications. Pastors need to understand these issues to minister effectively in an increasingly materialistic culture.

Cultural Challenges

Western culture increasingly assumes materialistic views of human nature. This affects everything from medical ethics to criminal justice to education. Christians need to be prepared to articulate and defend a biblical view of human nature in the public square.

At the same time, many people still intuitively believe they are more than their bodies. This provides an opportunity for evangelism and apologetics, showing how Christian faith makes sense of these deep human intuitions.

Conclusion: Standing Firm on Biblical Truth

After examining the philosophical, theological, and biblical evidence, the conclusion is clear: substance dualism remains the most faithful and coherent Christian view of human nature. Physicalism, despite its current popularity in some academic circles, creates insurmountable problems for essential Christian doctrines, especially the incarnation of Christ.

The stakes in this debate could not be higher. Our understanding of human nature affects our understanding of salvation, eternal life, spiritual growth, and most fundamentally, how God became human to save us. When physicalism undermines our ability to affirm that Jesus Christ is truly God and truly human in one person, it strikes at the very heart of the gospel.

The testimony of Scripture is clear. From Genesis to Revelation, the Bible consistently presents humans as having both physical and spiritual dimensions. Jesus himself affirmed the distinction between body and soul. The apostles taught that believers exist consciously with Christ between death and resurrection. The entire biblical narrative assumes and requires that humans are more than physical bodies.

The witness of the church throughout history is equally clear. For two thousand years, Christians have affirmed that humans have souls that can exist apart from their bodies. This wasn’t due to uncritical absorption of Greek philosophy but careful reflection on biblical teaching and its implications. The early church councils that formulated orthodox Christology explicitly affirmed that Christ has a rational soul as well as a body.

Philosophy and human experience support this biblical teaching. The unity of consciousness, personal identity through time, free will and moral responsibility – all these point to an immaterial soul that transcends physical processes. Even children naturally think in dualistic terms, suggesting this understanding is rooted in human nature itself rather than cultural conditioning.

Most importantly, dualism provides the necessary framework for understanding the incarnation without falling into heresy. Only if humans have both body and soul can we make sense of how the eternal Son of God became fully human while remaining fully divine. The attempt to maintain orthodox Christology while embracing physicalism leads inevitably to either impossibility or heresy.

As we face challenges to traditional Christian teaching about human nature, we must remember that truth is not determined by academic fashion or cultural trends but by God’s revelation in Scripture. The Bible teaches, the church has always believed, and sound reason confirms that humans are both body and soul. This understanding is not optional for Christian faith but essential to the gospel itself.

May we, like the great Presbyterian scholar J. Gresham Machen, not only hold that humans have souls but recognize the importance of knowing we have souls. For in this knowledge lies our understanding of our true nature, our relationship with God, our hope beyond death, and our confidence in the One who became flesh to save us – Jesus Christ, truly God and truly human, our Lord and Savior.

Appendix: Resources for Further Study

For those who wish to study these issues in greater depth, the following resources are recommended:

Books Defending Dualism:

• The Soul: How We Know It’s Real and Why It Matters by J.P. Moreland
• Body, Soul, and Life Everlasting by John Cooper
• The Emergent Self by William Hasker
• Mind, Brain, and Free Will by Richard Swinburne
• Christian Physicalism? A Philosophical Examination edited by Keith Loftin and Joshua Farris

Books on the Incarnation:

• The Logic of God Incarnate by Thomas Morris
• Divinity and Humanity by Oliver Crisp
• The Metaphysics of the Incarnation edited by Anna Marmodoro and Jonathan Hill

Historical Theology:

• The Christian Tradition (5 volumes) by Jaroslav Pelikan
• Historical Theology by Alister McGrath
• The writings of the Church Fathers, especially on Christology

Philosophical Works:

• The Conscious Mind by David Chalmers
• Philosophy of Mind by Edward Feser
• The Waning of Materialism edited by Robert Koons and George Bealer

Remember that this debate is not merely academic but has profound implications for Christian faith and life. Study these issues carefully, think deeply about them, but always return to Scripture as the final authority. Test all things by God’s Word, hold fast to what is good, and be prepared to give a reason for the hope that is within you.

The debate over human nature will likely continue for years to come. But as Christians committed to biblical truth, we must not waver in our conviction that humans are created as embodied souls, bearing God’s image in both our physical and spiritual dimensions. This truth is not peripheral but central to the gospel message and our hope in Christ.

May God grant His church wisdom, courage, and faithfulness as we defend and proclaim the full truth about human nature in an increasingly materialistic age. And may we never forget that our ultimate hope lies not in philosophical arguments but in the risen Christ, who in His own person demonstrates the reality of both body and soul, united in perfect harmony for all eternity.

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